Message handling for device-to-device coordination messages

ABSTRACT

Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a user equipment (UE) may drop a first one or more device-to-device coordination messages for transmission, of a set of device-to-device coordination messages, according to a message dropping criterion in connection with a quantity of device-to-device coordination messages in the set of device-to-device coordination messages exceeding a threshold. The UE may transmit a second one or more device-to-device coordination messages of the set of device-to-device coordination messages, such that a quantity of transmitted device-to-device coordination messages, of the set of device-to-device coordination messages, does not exceed the threshold. Numerous other aspects are described.

CROSS-REFERENCE TO RELATED APPLICATION

This Patent Application claims priority to U.S. Provisional PatentApplication No. 62/706,302, filed on Aug. 7, 2020, entitled “MESSAGEHANDLING FOR DEVICE-TO-DEVICE COORDINATION MESSAGES,” and assigned tothe assignee hereof. The disclosure of the prior Application isconsidered part of and is incorporated by reference into this PatentApplication.

INTRODUCTION

Aspects of the present disclosure generally relate to wirelesscommunication and to techniques and apparatuses for message handling indevice-to-device communication systems.

Wireless communication systems are widely deployed to provide varioustelecommunication services such as telephony, video, data, messaging,and broadcasts. Typical wireless communication systems may employmultiple-access technologies capable of supporting communication withmultiple users by sharing available system resources (e.g., bandwidth,transmit power, or the like). Examples of such multiple-accesstechnologies include code division multiple access (CDMA) systems, timedivision multiple access (TDMA) systems, frequency division multipleaccess (FDMA) systems, orthogonal frequency division multiple access(OFDMA) systems, single-carrier frequency division multiple access(SC-FDMA) systems, time division synchronous code division multipleaccess (TD-SCDMA) systems, and Long Term Evolution (LTE).LTE/LTE-Advanced is a set of enhancements to the Universal MobileTelecommunications System (UMTS) mobile standard promulgated by theThird Generation Partnership Project (3GPP).

A wireless network may include one or more base stations that supportcommunication for a user equipment (UE) or multiple UEs. A UE maycommunicate with a base station via downlink communications and uplinkcommunications. “Downlink” (or “DL”) refers to a communication link fromthe base station to the UE, and “uplink” (or “UL”) refers to acommunication link from the UE to the base station.

The above multiple access technologies have been adopted in varioustelecommunication standards to provide a common protocol that enablesdifferent UEs to communicate on a municipal, national, regional, and/orglobal level. New Radio (NR), which may be referred to as 5G, is a setof enhancements to the LTE mobile standard promulgated by the 3GPP. NRis designed to better support mobile broadband internet access byimproving spectral efficiency, lowering costs, improving services,making use of new spectrum, and better integrating with other openstandards using orthogonal frequency division multiplexing (OFDM) with acyclic prefix (CP) (CP-OFDM) on the downlink, using CP-OFDM and/orsingle-carrier frequency division multiplexing (SC-FDM) (also known asdiscrete Fourier transform spread OFDM (DFT-s-OFDM)) on the uplink, aswell as supporting beamforming, multiple-input multiple-output (MIMO)antenna technology, and carrier aggregation. As the demand for mobilebroadband access continues to increase, further improvements in LTE, NR,and other radio access technologies remain useful.

SUMMARY

Some aspects described herein relate to a user equipment (UE) forwireless communication. The user equipment may include a memory and oneor more processors coupled to the memory. The one or more processors maybe configured to drop a first one or more device-to-device coordinationmessages, of a set of device-to-device coordination messages fortransmission, according to a message dropping criterion in connectionwith a quantity of device-to-device coordination messages in the set ofdevice-to-device coordination messages exceeding a threshold. The one ormore processors may be configured to transmit a second one or moredevice-to-device coordination messages of the set of device-to-devicecoordination messages, such that a quantity of transmitteddevice-to-device coordination messages, of the set of device-to-devicecoordination messages, does not exceed the threshold.

Some aspects described herein relate to a non-transitorycomputer-readable medium that stores a set of instructions for wirelesscommunication by a UE. The set of instructions, when executed by one ormore processors of the UE, may cause the UE to drop a first one or moredevice-to-device coordination messages, of a set of device-to-devicecoordination messages for transmission, according to a message droppingcriterion in connection with a quantity of device-to-device coordinationmessages in the set of device-to-device coordination messages exceedinga threshold. The set of instructions, when executed by one or moreprocessors of the UE, may cause the UE to transmit a second one or moredevice-to-device coordination messages of the set of device-to-devicecoordination messages, such that a quantity of transmitteddevice-to-device coordination messages, of the set of device-to-devicecoordination messages, does not exceed the threshold.

Some aspects described herein relate to an apparatus for wirelesscommunication. The apparatus may include means for dropping a first oneor more device-to-device coordination messages, of a set ofdevice-to-device coordination messages for transmission, according to amessage dropping criterion in connection with a quantity ofdevice-to-device coordination messages in the set of device-to-devicecoordination messages exceeding a threshold. The apparatus may includemeans for transmitting a second one or more device-to-devicecoordination messages of the set of device-to-device coordinationmessages, such that a quantity of transmitted device-to-devicecoordination messages, of the set of device-to-device coordinationmessages, does not exceed the threshold.

Some aspects described herein relate to a method of wirelesscommunication performed by a UE. The method may include dropping a firstone or more device-to-device coordination messages for transmission, ofa set of device-to-device coordination messages, according to a messagedropping criterion in connection with a quantity of device-to-devicecoordination messages in the set of device-to-device coordinationmessages exceeding a threshold. The method may include transmitting asecond one or more device-to-device coordination messages of the set ofdevice-to-device coordination messages, such that a quantity oftransmitted device-to-device coordination messages, of the set ofdevice-to-device coordination messages, does not exceed the threshold.

In some aspects, a method of wireless communication performed by a UEincludes determining that a quantity of device-to-device coordinationmessages for transmission exceeds a threshold. The method may includedropping one or more device-to-device coordination messages according toa message dropping criterion based at least in part on determining thatthe quantity of device-to-device coordination messages exceeds thethreshold.

In some aspects, a UE for wireless communication includes a memory andone or more processors coupled to the memory, the one or more processorsconfigured to determine that a quantity of device-to-device coordinationmessages for transmission exceeds a threshold. The one or moreprocessors may be configured to drop one or more device-to-devicecoordination messages according to a message dropping criterion based atleast in part on determining that the quantity of device-to-devicecoordination messages exceeds the threshold.

In some aspects, a non-transitory computer-readable medium storing a setof instructions for wireless communication includes one or moreinstructions that, when executed by one or more processors of a UE,cause the UE to determine that a quantity of device-to-devicecoordination messages for transmission exceeds a threshold and drop oneor more device-to-device coordination messages according to a messagedropping criterion based at least in part on determining that thequantity of device-to-device coordination messages exceeds thethreshold.

In some aspects, an apparatus for wireless communication includes meansfor determining that a quantity of device-to-device coordinationmessages for transmission exceeds a threshold. The apparatus includesmeans for dropping one or more device-to-device coordination messagesaccording to a message dropping criterion based at least in part ondetermining that the quantity of device-to-device coordination messagesexceeds the threshold.

Aspects generally include a method, apparatus, system, computer programproduct, non-transitory computer-readable medium, user equipment, basestation, wireless communication device, and/or processing system assubstantially described with reference to and as illustrated by thedrawings and specification.

The foregoing has outlined rather broadly the features and technicaladvantages of examples according to the disclosure in order that thedetailed description that follows may be better understood. Additionalfeatures and advantages will be described hereinafter. The conceptionand specific examples disclosed may be readily utilized as a basis formodifying or designing other structures for carrying out the samepurposes of the present disclosure. Such equivalent constructions do notdepart from the scope of the appended claims Characteristics of theconcepts disclosed herein, both their organization and method ofoperation, together with associated advantages will be better understoodfrom the following description when considered in connection with theaccompanying figures. Each of the figures is provided for the purpose ofillustration and description, and not as a definition of the limits ofthe claims.

BRIEF DESCRIPTION OF THE DRAWINGS

So that the above-recited features of the present disclosure can beunderstood in detail, a more particular description, briefly summarizedabove, may be had by reference to aspects, some of which are illustratedin the appended drawings. It is to be noted, however, that the appendeddrawings illustrate only certain typical aspects of this disclosure andare therefore not to be considered limiting of its scope, for thedescription may admit to other equally effective aspects. The samereference numbers in different drawings may identify the same or similarelements.

FIG. 1 is a diagram illustrating an example of a wireless network, inaccordance with the present disclosure.

FIG. 2 is a diagram illustrating an example of a base station incommunication with a user equipment (UE) in a wireless network, inaccordance with the present disclosure.

FIG. 3 is a diagram illustrating an example of device-to-devicecommunications, in accordance with the present disclosure.

FIG. 4 is a diagram illustrating an example of device-to-devicecommunications and access link communications, in accordance with thepresent disclosure.

FIGS. 5A and 5B are diagrams illustrating examples of requesting andreporting resources for sidelink inter-UE coordination information, inaccordance with the present disclosure.

FIG. 6 is a diagram illustrating an example of resource sensing forsidelink inter-UE coordination, in accordance with the presentdisclosure.

FIG. 7 is a diagram illustrating an example associated with coordinationsignaling, in accordance with the present disclosure.

FIG. 8 is a diagram illustrating an example associated with messagehandling for device-to-device coordination messages, in accordance withthe present disclosure.

FIG. 9 is a diagram illustrating an example process associated withmessage handling for device-to-device coordination messages, inaccordance with the present disclosure.

FIG. 10 is a diagram of an example apparatus for wireless communication,in accordance with the present disclosure.

FIG. 11 is a diagram illustrating an example of a hardwareimplementation for an apparatus employing a processing system, inaccordance with the present disclosure.

FIG. 12 is a diagram illustrating an example implementation of code andcircuitry for an apparatus, in accordance with the present disclosure.

DETAILED DESCRIPTION

A user equipment (UE) engaged in device-to-device communication, such assidelink communication, may be configured with resources that are to beused to transmit device-to-device coordination messages, such assidelink inter-UE coordination information messages. For example, afirst UE may receive, from a second UE and a third UE, a request for asidelink inter-UE coordination message. The first UE may performresource sensing to determine whether resources are available and maytransmit the sidelink inter-UE coordination message to the second UE andthe third UE to identify reserved resources and available resources in aselection window. This may enable the second UE and the third UE,respectively, to select resources for transmission. Additionally, oralternatively, the first UE may provide the sidelink inter-UEcoordination message to the second UE to enable the second UE to selecttransmission resources for the third UE (and the second UE may indicatethe selected transmission resources to the third UE). However, in somescenarios, the first UE may have a plurality of sidelink inter-UEcoordination messages requested for transmission using the sameresources. In some other scenarios, the first UE may have more sidelinkinter-UE coordination messages requested for concurrent transmissionthan the first UE has a capability of concurrently transmitting.

Some aspects described herein enable message handling fordevice-to-device coordination messages, such as sidelink inter-UEcoordination messages. For example, the first UE may prioritize aplurality of sidelink inter-UE coordination messages that are requestedfor transmission. Based at least in part on the prioritization, thefirst UE may drop or delay one or more of the plurality of sidelinkinter-UE coordination messages. In this way, the first UE handlesconflicting or excess requests for sidelink inter-UE coordinationmessages.

Various aspects of the disclosure are described more fully hereinafterwith reference to the accompanying drawings. This disclosure may,however, be embodied in many different forms and should not be construedas limited to any specific structure or function presented throughoutthis disclosure. Rather, these aspects are provided so that thisdisclosure will be thorough and complete, and will fully convey thescope of the disclosure to those skilled in the art. One skilled in theart should appreciate that the scope of the disclosure is intended tocover any aspect of the disclosure disclosed herein, whether implementedindependently of or combined with any other aspect of the disclosure.For example, an apparatus may be implemented or a method may bepracticed using any number of the aspects set forth herein. In addition,the scope of the disclosure is intended to cover such an apparatus ormethod which is practiced using other structure, functionality, orstructure and functionality in addition to or other than the variousaspects of the disclosure set forth herein. It should be understood thatany aspect of the disclosure disclosed herein may be embodied by one ormore elements of a claim.

Several aspects of telecommunication systems will now be presented withreference to various apparatuses and techniques. These apparatuses andtechniques will be described in the following detailed description andillustrated in the accompanying drawings by various blocks, modules,components, circuits, steps, processes, algorithms, or the like(collectively referred to as “elements”). These elements may beimplemented using hardware, software, or combinations thereof. Whethersuch elements are implemented as hardware or software depends upon theparticular application and design constraints imposed on the overallsystem.

While aspects may be described herein using terminology commonlyassociated with a 5G or New Radio (NR) radio access technology (RAT),aspects of the present disclosure can be applied to other RATs, such asa 3G RAT, a 4G RAT, and/or a RAT subsequent to 5G (e.g., 6G).

FIG. 1 is a diagram illustrating an example of a wireless network 100,in accordance with the present disclosure. The wireless network 100 maybe or may include elements of a 5G (e.g., NR) network and/or a 4G (e.g.,Long Term Evolution (LTE)) network, among other examples. The wirelessnetwork 100 may include one or more base stations 110 (shown as a BS 110a, a BS 110 b, a BS 110 c, and a BS 110 d), a UE 120 or multiple UEs 120(shown as a UE 120 a, a UE 120 b, a UE 120 c, a UE 120 d, and a UE 120e), and/or other network entities. A base station 110 is an entity thatcommunicates with UEs 120. A base station 110 (sometimes referred to asa BS) may include, for example, an NR base station, an LTE base station,a Node B, an eNB (e.g., in 4G), a gNB (e.g., in 5G), an access point,and/or a transmission reception point (TRP). Each base station 110 mayprovide communication coverage for a particular geographic area. In theThird Generation Partnership Project (3GPP), the term “cell” can referto a coverage area of a base station 110 and/or a base station subsystemserving this coverage area, depending on the context in which the termis used.

A base station 110 may provide communication coverage for a macro cell,a pico cell, a femto cell, and/or another type of cell. A macro cell maycover a relatively large geographic area (e.g., several kilometers inradius) and may allow unrestricted access by UEs 120 with servicesubscriptions. A pico cell may cover a relatively small geographic areaand may allow unrestricted access by UEs 120 with service subscription.A femto cell may cover a relatively small geographic area (e.g., a home)and may allow restricted access by UEs 120 having association with thefemto cell (e.g., UEs 120 in a closed subscriber group (CSG)). A basestation 110 for a macro cell may be referred to as a macro base station.A base station 110 for a pico cell may be referred to as a pico basestation. A base station 110 for a femto cell may be referred to as afemto base station or an in-home base station. In the example shown inFIG. 1 , the BS 110 a may be a macro base station for a macro cell 102a, the BS 110 b may be a pico base station for a pico cell 102 b, andthe BS 110 c may be a femto base station for a femto cell 102 c. A basestation may support one or multiple (e.g., three) cells.

In some examples, a cell may not necessarily be stationary, and thegeographic area of the cell may move according to the location of a basestation 110 that is mobile (e.g., a mobile base station). In someexamples, the base stations 110 may be interconnected to one anotherand/or to one or more other base stations 110 or network nodes (notshown) in the wireless network 100 through various types of backhaulinterfaces, such as a direct physical connection or a virtual network,using any suitable transport network.

The wireless network 100 may include one or more relay stations. A relaystation is an entity that can receive a transmission of data from anupstream station (e.g., a base station 110 or a UE 120) and send atransmission of the data to a downstream station (e.g., a UE 120 or abase station 110). A relay station may be a UE 120 that can relaytransmissions for other UEs 120. In the example shown in FIG. 1 , the BS110 d (e.g., a relay base station) may communicate with the BS 110 a(e.g., a macro base station) and the UE 120 d in order to facilitatecommunication between the BS 110 a and the UE 120 d. A base station 110that relays communications may be referred to as a relay station, arelay base station, a relay, or the like.

The wireless network 100 may be a heterogeneous network that includesbase stations 110 of different types, such as macro base stations, picobase stations, femto base stations, relay base stations, or the like.These different types of base stations 110 may have different transmitpower levels, different coverage areas, and/or different impacts oninterference in the wireless network 100. For example, macro basestations may have a high transmit power level (e.g., 5 to 40 watts)whereas pico base stations, femto base stations, and relay base stationsmay have lower transmit power levels (e.g., 0.1 to 2 watts).

A network controller 130 may couple to or communicate with a set of basestations 110 and may provide coordination and control for these basestations 110. The network controller 130 may communicate with the basestations 110 via a backhaul communication link. The base stations 110may communicate with one another directly or indirectly via a wirelessor wireline backhaul communication link.

The UEs 120 may be dispersed throughout the wireless network 100, andeach UE 120 may be stationary or mobile. A UE 120 may include, forexample, an access terminal, a terminal, a mobile station, and/or asubscriber unit. A UE 120 may be a cellular phone (e.g., a smart phone),a personal digital assistant (PDA), a wireless modem, a wirelesscommunication device, a handheld device, a laptop computer, a cordlessphone, a wireless local loop (WLL) station, a tablet, a camera, a gamingdevice, a netbook, a smartbook, an ultrabook, a medical device, abiometric device, a wearable device (e.g., a smart watch, smartclothing, smart glasses, a smart wristband, smart jewelry (e.g., a smartring or a smart bracelet)), an entertainment device (e.g., a musicdevice, a video device, and/or a satellite radio), a vehicular componentor sensor, a smart meter/sensor, industrial manufacturing equipment, aglobal positioning system device, and/or any other suitable device thatis configured to communicate via a wireless or wired medium.

Some UEs 120 may be considered machine-type communication (MTC) orevolved or enhanced machine-type communication (eMTC) UEs. An MTC UEand/or an eMTC UE may include, for example, a robot, a drone, a remotedevice, a sensor, a meter, a monitor, and/or a location tag, that maycommunicate with a base station, another device (e.g., a remote device),or some other entity. Some UEs 120 may be considered Internet-of-Things(IoT) devices, and/or may be implemented as NB-IoT (narrowband IoT)devices. Some UEs 120 may be considered a Customer Premises Equipment. AUE 120 may be included inside a housing that houses components of the UE120, such as processor components and/or memory components. In someexamples, the processor components and the memory components may becoupled together. For example, the processor components (e.g., one ormore processors) and the memory components (e.g., a memory) may beoperatively coupled, communicatively coupled, electronically coupled,and/or electrically coupled.

In general, any number of wireless networks 100 may be deployed in agiven geographic area. Each wireless network 100 may support aparticular RAT and may operate on one or more frequencies. A RAT may bereferred to as a radio technology, an air interface, or the like. Afrequency may be referred to as a carrier, a frequency channel, or thelike. Each frequency may support a single RAT in a given geographic areain order to avoid interference between wireless networks of differentRATs. In some cases, NR or 5G RAT networks may be deployed.

In some examples, two or more UEs 120 (e.g., shown as UE 120 a and UE120 e) may communicate directly using one or more sidelink channels(e.g., without using a base station 110 as an intermediary tocommunicate with one another). For example, the UEs 120 may communicateusing peer-to-peer (P2P) communications, device-to-device (D2D)communications, a vehicle-to-everything (V2X) protocol (e.g., which mayinclude a vehicle-to-vehicle (V2V) protocol, a vehicle-to-infrastructure(V2I) protocol, or a vehicle-to-pedestrian (V2P) protocol), and/or amesh network. In such examples, a UE 120 may perform schedulingoperations, resource selection operations, and/or other operationsdescribed elsewhere herein as being performed by the base station 110.

The electromagnetic spectrum is often subdivided, byfrequency/wavelength, into various classes, bands, channels, etc. In 5GNR, two initial operating bands have been identified as frequency rangedesignations FR1 (410 MHz-7.125 GHz) and FR2 (24.25 GHz-52.6 GHz). Itshould be understood that although a portion of FR1 is greater than 6GHz, FR1 is often referred to (interchangeably) as a “Sub-6 GHz” band invarious documents and articles. A similar nomenclature issue sometimesoccurs with regard to FR2, which is often referred to (interchangeably)as a “millimeter wave” band in documents and articles, despite beingdifferent from the extremely high frequency (EHF) band (30 GHz-300 GHz)which is identified by the International Telecommunications Union (ITU)as a “millimeter wave” band.

The frequencies between FR1 and FR2 are often referred to as mid-bandfrequencies. Recent 5G NR studies have identified an operating band forthese mid-band frequencies as frequency range designation FR3 (7.125GHz-24.25 GHz). Frequency bands falling within FR3 may inherit FR1characteristics and/or FR2 characteristics, and thus may effectivelyextend features of FR1 and/or FR2 into mid-band frequencies. Inaddition, higher frequency bands are currently being explored to extend5G NR operation beyond 52.6 GHz. For example, three higher operatingbands have been identified as frequency range designations FR4a or FR4-1(52.6 GHz-71 GHz), FR4 (52.6 GHz-114.25 GHz), and FR5 (114.25 GHz-300GHz). Each of these higher frequency bands falls within the EHF band.

With the above examples in mind, unless specifically stated otherwise,it should be understood that the term “sub-6 GHz” or the like, if usedherein, may broadly represent frequencies that may be less than 6 GHz,may be within FR1, or may include mid-band frequencies. Further, unlessspecifically stated otherwise, it should be understood that the term“millimeter wave” or the like, if used herein, may broadly representfrequencies that may include mid-band frequencies, may be within FR2,FR4, FR4-a or FR4-1, and/or FR5, or may be within the EHF band. It iscontemplated that the frequencies included in these operating bands(e.g., FR1, FR2, FR3, FR4, FR4-a, FR4-1, and/or FR5) may be modified,and techniques described herein are applicable to those modifiedfrequency ranges.

In some aspects, the UE 120 may include a communication manager 140. Asdescribed in more detail elsewhere herein, the communication manager 140may drop a first one or more device-to-device coordination messages, ofa set of device-to-device coordination messages for transmission,according to a message dropping criterion in connection with a quantityof device-to-device coordination messages in the set of device-to-devicecoordination messages exceeding a threshold; and transmit a second oneor more device-to-device coordination messages of the set ofdevice-to-device coordination messages, such that a quantity oftransmitted device-to-device coordination messages, of the set ofdevice-to-device coordination messages, does not exceed the threshold.Additionally, or alternatively, the communication manager 140 mayperform one or more other operations described herein.

As indicated above, FIG. 1 is provided as an example. Other examples maydiffer from what is described with regard to FIG. 1 .

FIG. 2 is a diagram illustrating an example 200 of a base station 110 incommunication with a UE 120 in a wireless network 100, in accordancewith the present disclosure. The base station 110 may be equipped with aset of antennas 234 a through 234 t, such as T antennas (T≥1). The UE120 may be equipped with a set of antennas 252 a through 252 r, such asR antennas (R≥1).

At the base station 110, a transmit processor 220 may receive data, froma data source 212, intended for the UE 120 (or a set of UEs 120). Thetransmit processor 220 may select one or more modulation and codingschemes (MCSs) for the UE 120 based at least in part on one or morechannel quality indicators (CQIs) received from that UE 120. The UE 120may process (e.g., encode and modulate) the data for the UE 120 based atleast in part on the MCS(s) selected for the UE 120 and may provide datasymbols for the UE 120. The transmit processor 220 may process systeminformation (e.g., for semi-static resource partitioning information(SRPI)) and control information (e.g., CQI requests, grants, and/orupper layer signaling) and provide overhead symbols and control symbols.The transmit processor 220 may generate reference symbols for referencesignals (e.g., a cell-specific reference signal (CRS) or a demodulationreference signal (DMRS)) and synchronization signals (e.g., a primarysynchronization signal (PSS) or a secondary synchronization signal(SSS)). A transmit (TX) multiple-input multiple-output (MIMO) processor230 may perform spatial processing (e.g., precoding) on the datasymbols, the control symbols, the overhead symbols, and/or the referencesymbols, if applicable, and may provide a set of output symbol streams(e.g., T output symbol streams) to a corresponding set of modems 232(e.g., T modems), shown as modems 232 a through 232 t. For example, eachoutput symbol stream may be provided to a modulator component (shown asMOD) of a modem 232. Each modem 232 may use a respective modulatorcomponent to process a respective output symbol stream (e.g., for OFDM)to obtain an output sample stream. Each modem 232 may further use arespective modulator component to process (e.g., convert to analog,amplify, filter, and/or upconvert) the output sample stream to obtain adownlink signal. The modems 232 a through 232 t may transmit a set ofdownlink signals (e.g., T downlink signals) via a corresponding set ofantennas 234 (e.g., T antennas), shown as antennas 234 a through 234 t.

At the UE 120, a set of antennas 252 (shown as antennas 252 a through252 r) may receive the downlink signals from the base station 110 and/orother base stations 110 and may provide a set of received signals (e.g.,R received signals) to a set of modems 254 (e.g., R modems), shown asmodems 254 a through 254 r. For example, each received signal may beprovided to a demodulator component (shown as DEMOD) of a modem 254.Each modem 254 may use a respective demodulator component to condition(e.g., filter, amplify, downconvert, and/or digitize) a received signalto obtain input samples. Each modem 254 may use a demodulator componentto further process the input samples (e.g., for OFDM) to obtain receivedsymbols. A MIMO detector 256 may obtain received symbols from the modems254, may perform MIMO detection on the received symbols if applicable,and may provide detected symbols. A receive processor 258 may process(e.g., demodulate and decode) the detected symbols, may provide decodeddata for the UE 120 to a data sink 260, and may provide decoded controlinformation and system information to a controller/processor 280. Theterm “controller/processor” may refer to one or more controllers, one ormore processors, or a combination thereof. A channel processor maydetermine a reference signal received power (RSRP) parameter, a receivedsignal strength indicator (RSSI) parameter, a reference signal receivedquality (RSRQ) parameter, and/or a CQI parameter, among other examples.In some examples, one or more components of the UE 120 may be includedin a housing.

The network controller 130 may include a communication unit 294, acontroller/processor 290, and a memory 292. The network controller 130may include, for example, one or more devices in a core network. Thenetwork controller 130 may communicate with the base station 110 via thecommunication unit 294.

One or more antennas (e.g., antennas 234 a through 234 t and/or antennas252 a through 252 r) may include, or may be included within, one or moreantenna panels, one or more antenna groups, one or more sets of antennaelements, and/or one or more antenna arrays, among other examples. Anantenna panel, an antenna group, a set of antenna elements, and/or anantenna array may include one or more antenna elements (within a singlehousing or multiple housings), a set of coplanar antenna elements, a setof non-coplanar antenna elements, and/or one or more antenna elementscoupled to one or more transmission and/or reception components, such asone or more components of FIG. 2 .

On the uplink, at the UE 120, a transmit processor 264 may receive andprocess data from a data source 262 and control information (e.g., forreports that include RSRP, RSSI, RSRQ, and/or CQI) from thecontroller/processor 280. The transmit processor 264 may generatereference symbols for one or more reference signals. The symbols fromthe transmit processor 264 may be precoded by a TX MIMO processor 266 ifapplicable, further processed by the modems 254 (e.g., for DFT-s-OFDM orCP-OFDM), and transmitted to the base station 110. In some examples, themodem 254 of the UE 120 may include a modulator and a demodulator. Insome examples, the UE 120 includes a transceiver. The transceiver mayinclude any combination of the antenna(s) 252, the modem(s) 254, theMIMO detector 256, the receive processor 258, the transmit processor264, and/or the TX MIMO processor 266. The transceiver may be used by aprocessor (e.g., the controller/processor 280) and the memory 282 toperform aspects of any of the methods described herein.

At the base station 110, the uplink signals from UE 120 and/or other UEsmay be received by the antennas 234, processed by the modem 232 (e.g., ademodulator component, shown as DEMOD, of the modem 232), detected by aMIMO detector 236 if applicable, and further processed by a receiveprocessor 238 to obtain decoded data and control information sent by theUE 120. The receive processor 238 may provide the decoded data to a datasink 239 and provide the decoded control information to thecontroller/processor 240. The base station 110 may include acommunication unit 244 and may communicate with the network controller130 via the communication unit 244. The base station 110 may include ascheduler 246 to schedule one or more UEs 120 for downlink and/or uplinkcommunications. In some examples, the modem 232 of the base station 110may include a modulator and a demodulator. In some examples, the basestation 110 includes a transceiver. The transceiver may include anycombination of the antenna(s) 234, the modem(s) 232, the MIMO detector236, the receive processor 238, the transmit processor 220, and/or theTX MIMO processor 230. The transceiver may be used by a processor (e.g.,the controller/processor 240) and the memory 242 to perform aspects ofany of the methods described herein.

The controller/processor 240 of the base station 110, thecontroller/processor 280 of the UE 120, and/or any other component(s) ofFIG. 2 may perform one or more techniques associated with messagehandling for device-to-device coordination messages, as described inmore detail elsewhere herein. For example, the controller/processor 240of the base station 110, the controller/processor 280 of the UE 120,and/or any other component(s) of FIG. 2 may perform or direct operationsof, for example, process 900 of FIG. 9 and/or other processes asdescribed herein. The memory 242 and the memory 282 may store data andprogram codes for the base station 110 and the UE 120, respectively. Insome examples, the memory 242 and/or the memory 282 may include anon-transitory computer-readable medium storing one or more instructions(e.g., code and/or program code) for wireless communication. Forexample, the one or more instructions, when executed (e.g., directly, orafter compiling, converting, and/or interpreting) by one or moreprocessors of the base station 110 and/or the UE 120, may cause the oneor more processors, the UE 120, and/or the base station 110 to performor direct operations of, for example, process 900 of FIG. 9 and/or otherprocesses as described herein. In some examples, executing instructionsmay include running the instructions, converting the instructions,compiling the instructions, and/or interpreting the instructions, amongother examples.

In some aspects, the UE includes means for dropping a first one or moredevice-to-device coordination messages, of a set of device-to-devicecoordination messages, according to a message dropping criterion inconnection with a total quantity of device-to-device coordinationmessages in the set of device-to-device coordination messages exceedinga threshold; and/or means for transmitting a second one or moredevice-to-device coordination messages of the set of device-to-devicecoordination messages, such that a sub-quantity of transmitteddevice-to-device coordination messages does not exceed the threshold.The means for the UE to perform operations described herein may include,for example, one or more of communication manager 140, antenna 252,modem 254, MIMO detector 256, receive processor 258, transmit processor264, TX MIMO processor 266, controller/processor 280, or memory 282.

While blocks in FIG. 2 are illustrated as distinct components, thefunctions described above with respect to the blocks may be implementedin a single hardware, software, or combination component or in variouscombinations of components. For example, the functions described withrespect to the transmit processor 264, the receive processor 258, and/orthe TX MIMO processor 266 may be performed by or under the control ofthe controller/processor 280.

As indicated above, FIG. 2 is provided as an example. Other examples maydiffer from what is described with regard to FIG. 2 .

FIG. 3 is a diagram illustrating an example 300 of device-to-devicecommunications, in accordance with the present disclosure.

As shown in FIG. 3 , a first UE 305-1, which may correspond to UE 120 a,may communicate with a second UE 305-2, which may correspond to UE 120e, (and one or more other UEs 305) via one or more sidelink channels310, which may be an example of device-to-device communications. The UEs305-1 and 305-2 may communicate using the one or more sidelink channels310 for P2P communications, D2D communications, V2X communications(e.g., which may include V2V communications, V2I communications, V2Pcommunications, a combination thereof, and/or the like), meshnetworking, a combination thereof, and/or the like. In some aspects, theUEs 305 (e.g., UE 305-1 and/or UE 305-2) may correspond to one or moreother UEs described elsewhere herein, such as UE 120. In some aspects,the one or more sidelink channels 310 may use a PC5 interface and/or mayoperate in a high frequency band (e.g., the 5.9 GHz band). Additionally,or alternatively, the UEs 305 may synchronize timing of transmissiontime intervals (TTIs) (e.g., frames, subframes, slots, symbols, acombination thereof, and/or the like) using global navigation satellitesystem (GNSS) timing.

As further shown in FIG. 3 , the one or more sidelink channels 310 mayinclude a physical sidelink control channel (PSCCH) 315, a physicalsidelink shared channel (PSSCH) 320, and/or a physical sidelink feedbackchannel (PSFCH) 325. The PSCCH 315 may be used to communicate controlinformation, similar to a physical downlink control channel (PDCCH)and/or a physical uplink control channel (PUCCH) used for cellularcommunications with a base station 110 via an access link or an accesschannel. The PSSCH 320 may be used to communicate data, similar to aphysical downlink shared channel (PDSCH) and/or a physical uplink sharedchannel (PUSCH) used for cellular communications with a base station 110via an access link or an access channel. For example, the PSCCH 315 maycarry sidelink control information (SCI) 330, which may indicate variouscontrol information used for sidelink communications, such as one ormore resources (e.g., time resources, frequency resources, spatialresources, a combination thereof, and/or the like) where a transportblock (TB) 335 may be carried on the PSSCH 320. The TB 335 may includedata. The PSFCH 325 may be used to communicate sidelink feedback 340,such as hybrid automatic repeat request (HARQ) feedback (e.g.,acknowledgement or negative acknowledgement (ACK/NACK) information),transmit power control (TPC), a scheduling request (SR), a combinationthereof, and/or the like.

In some aspects, the one or more sidelink channels 310 may use resourcepools. For example, a scheduling assignment (e.g., included in SCI 330)may be transmitted in sub-channels using specific resource blocks (RBs)across time. In some aspects, data transmissions (e.g., on the PSSCH320) associated with a scheduling assignment may occupy adjacent RBs inthe same subframe as the scheduling assignment (e.g., using frequencydivision multiplexing). In some aspects, a scheduling assignment andassociated data transmissions are not transmitted on adjacent RBs.

In some aspects, a UE 305 may operate using a transmission mode whereresource selection and/or scheduling is performed by the UE 305 (e.g.,rather than a base station 110). In some aspects, the UE 305 may performresource selection and/or scheduling by sensing channel availability fortransmissions. For example, the UE 305 may measure an RSSI parameter(e.g., a sidelink-RSSI (S-RSSI) parameter) associated with varioussidelink channels, may measure an RSRP parameter (e.g., a PSSCH-RSRPparameter) associated with various sidelink channels, may measure anRSRQ parameter (e.g., a PSSCH-RSRQ parameter) associated with varioussidelink channels, a combination thereof, and/or the like, and mayselect a channel for transmission of a sidelink communication based atleast in part on the measurement(s).

Additionally, or alternatively, the UE 305 may perform resourceselection and/or scheduling using SCI 330 received in the PSCCH 315,which may indicate occupied resources, channel parameters, a combinationthereof, and/or the like. Additionally, or alternatively, the UE 305 mayperform resource selection and/or scheduling by determining a channelbusy rate (CBR) associated with various sidelink channels, which may beused for rate control (e.g., by indicating a maximum number of resourceblocks that the UE 305 can use for a particular set of subframes).

In the transmission mode where resource selection and/or scheduling isperformed by a UE 305, the UE 305 may generate sidelink grants, and maytransmit the grants in SCI 330. A sidelink grant may indicate, forexample, one or more parameters (e.g., transmission parameters) to beused for an upcoming sidelink transmission, such as one or more resourceblocks to be used for the upcoming sidelink transmission on the PSSCH320 (e.g., for TBs 335), one or more subframes to be used for theupcoming sidelink transmission, an MCS to be used for the upcomingsidelink transmission, a combination thereof, and/or the like. In someaspects, a UE 305 may generate a sidelink grant that indicates one ormore parameters for semi-persistent scheduling (SPS), such as aperiodicity of a sidelink transmission. Additionally, or alternatively,the UE 305 may generate a sidelink grant for event-driven scheduling,such as for an on-demand sidelink message.

As indicated above, FIG. 3 is provided as an example. Other examples maydiffer from what is described with respect to FIG. 3 .

FIG. 4 is a diagram illustrating an example 400 of device-to-devicecommunications and access link communications, in accordance withvarious aspects of the present disclosure.

As shown in FIG. 4 , a transmitter (Tx)/receiver (Rx) UE 405, which maycorrespond to UE 120 a, and an Rx/Tx UE 410, which may correspond to UE120 e, may communicate with one another via a sidelink, which may be anexample of a device-to-device link, as described above in connectionwith FIG. 3 . As further shown, in some sidelink modes, a base station110 may communicate with the Tx/Rx UE 405 via a first access link.Additionally, or alternatively, in some sidelink modes, the base station110 may communicate with the Rx/Tx UE 410 via a second access link. TheTx/Rx UE 405 and/or the Rx/Tx UE 410 may correspond to one or more UEsdescribed elsewhere herein, such as the UE 120 of FIG. 1 . Thus, adirect link between UEs 120 (e.g., via a PC5 interface) may be referredto as a sidelink, and a direct link between a base station 110 and a UE120 (e.g., via a Uu interface) may be referred to as an access link.Sidelink communications may be transmitted via the sidelink, and accesslink communications may be transmitted via the access link. An accesslink communication may be either a downlink communication (from a basestation 110 to a UE 120) or an uplink communication (from a UE 120 to abase station 110).

As indicated above, FIG. 4 is provided as an example. Other examples maydiffer from what is described with respect to FIG. 4 .

FIGS. 5A and 5B are diagrams illustrating examples 500 and 550 ofrequesting and reporting resources for sidelink inter-UE coordinationinformation, in accordance with various aspects of the presentdisclosure.

A UE engaged in device-to-device communication, such as sidelinkcommunication, may be configured with resources 505 that are to be usedto transmit and/or receive requests for sidelink inter-UE coordinationinformation (which may be referred to as requesting resources), and/orresources 510 that are to be used to transmit and/or receive reports ofsidelink inter-UE coordination information (which may be referred to asreporting resources). A requesting resource 505 or a reporting resource510 may include one or more sub-channels (e.g., of a sidelink resourcepool) in a frequency domain and one slot in a time domain, however otherconfigurations are possible. In some aspects, a reporting resource 510and a requesting resource 505 may differ in size in a frequency domainand/or in a time domain.

The requesting resources 505 and the reporting resources 510 may beconfigured with a particular periodicity (e.g., the requesting resources505 and the reporting resources 510 may be configured with the sameperiodicity or different periodicities). Each periodic occasion of therequesting resources 505 may be referred to as a requesting occasion515, and each periodic occasion of the reporting resources 510 may bereferred to as a reporting occasion 520. The reporting occasions 520 onthe right side of FIGS. 5A and 5B are shown enlarged to illustrate thereporting resources 510.

In some aspects, if inter-UE coordination information is requested in aparticular requesting occasion 515, then responsive inter-UEcoordination information may be reported in the next reporting occasion520 following the particular requesting occasion 515. That is, arequesting occasion 515 may be associated with a reporting occasion 520that is to be used for responding to a request for inter-UE coordinationinformation that was transmitted in the requesting occasion 515.

In some aspects, a requesting resource 505 may be mapped to one or morereporting resources 510. For example, in the examples 500 and 550, arequesting resource 505 shown with a particular fill may be mapped toone or more reporting resources 510 shown in the same fill. A UE may beconfigured with a mapping between requesting resources 505 and reportingresources 510, such as in a sidelink resource pool configuration. Themapping may indicate particular reporting resource(s) 510 that are to beused for responding to a request for inter-UE coordination informationthat was transmitted in a particular requesting resource 505 (e.g.,according to a mapping between the particular requesting resource 505and the particular reporting resource(s) 510).

In the example 500, the requesting resources 505 may be in a singlerequesting occasion 515 per period. That is, the requesting resources505 may be in a single sidelink slot per period. In one or moreexamples, the single requesting occasion 515 may be associated with asingle reporting occasion 520 per period.

In the example 550, the requesting resources 505 may be distributed overmultiple requesting occasions 515 per period. That is, the requestingresources 505 may be in multiple slots per period. In one or moreexamples, the multiple requesting occasions 515 may be associated with asingle reporting occasion 520 per period.

As indicated above, FIGS. 5A and 5B are provided as examples. Otherexamples may differ from what is described with respect to FIGS. 5A and5B.

FIG. 6 is a diagram illustrating an example 600 of resource sensing forsidelink inter-UE coordination, in accordance with various aspects ofthe present disclosure.

As shown in FIG. 6 , during a sensing window, a UE A (which maycorrespond to, for example, UE 120 a) may coordinate with other UEs,such as a UE B (which may correspond to, for example, UE 120 e) and a UEC (which may correspond to, for example, UE 120 f). For example, UEs Band C may request assistance from UE A in determining whether resourcesare available for communication. In another example, UE A may receive arequest from a BS or a relay BS to assist with inter-UE coordination. Inyet another example, UE A may autonomously determine to transmit aninter-UE coordination message, such as based at least in part onobserved network conditions.

UE A may, during a sensing window, monitor for resource availability.The UE A may detect a request for resources from, for example, UE B, UEC, and other UEs. In some cases, UE A may experience a processing delaybetween when UE A detects a request for resources and when UE A hasprocessed the request and is triggered to transmit an inter-UEcoordination message to identify whether resources are available.

As further shown in FIG. 6 , UE A may transmit reporting regardingwhether resources are available to UE B, UE C, and/or other UEs. Thetransmission of the reporting may occur a threshold processing timebefore a selection window during which UE A, UE B, UE C, and other UEsmay use resources that UE A has identified as available of unavailable.For example, as shown, UE A identifies one or more resources asavailable to UE B and UE C and other resources as unavailable to UE Band U C.

As indicated above, FIG. 6 is provided as an example. Other examples maydiffer from what is described with respect to FIG. 6 .

FIG. 7 is a diagram illustrating an example 700 of coordinationsignaling, in accordance with various aspects of the present disclosure.

In example 700, a first UE (e.g., UE 120 a) exchanges inter-UEcoordination signaling with a second UE (e.g., UE 120 e). The first UEand the second UE may operate in an in-coverage mode, a partial coveragemode, an out-of-coverage mode, a combination thereof, and/or the like.For example, the first UE may determine a set of sidelink resourcesavailable for a resource allocation. The first UE may determine the setof sidelink resources based at least in part on determining that the setof sidelink resources are to be selected, or based at least in part on arequest, referred to herein as an inter-UE coordination request,received from the second UE or a base station. In some aspects, thefirst UE may determine the set of sidelink resources based at least inpart on a sensing operation, which may be performed before receiving aninter-UE coordination request or after receiving the inter-UEcoordination request. The first UE may transmit the set of availableresources to the second UE via inter-UE coordination signaling (shown asa coordination message, and which may be referred to as an inter-UEcoordination message). The first UE may transmit the set of availableresources using an NR sidelink resource allocation mode 2. In the NRsidelink resource allocation mode 2, resource allocation is handled byUEs (e.g., in comparison to an NR sidelink resource allocation mode 1,in which resource allocation is handled by a scheduling entity such as abase station). The second UE may select a sidelink resource for atransmission from the second UE based at least in part on the set ofavailable resources received from the first UE. As shown, the second UEmay perform the transmission accounting for the coordination information(e.g., via a sidelink resource indicated by the inter-UE coordinationmessage, a combination thereof, and/or the like). Inter-UE coordinationsignaling related to resource allocation may reduce collisions betweenthe first UE and the second UE. Inter-UE coordination signaling relatedto resource allocation may reduce a power consumption for the first UEand/or the second UE.

As indicated above, FIG. 7 is provided as an example. Other examples maydiffer from what is described with respect to FIG. 7 .

As described above, a first UE may receive a request to transmit adevice-to-device coordination message from a second UE, a third UE, aBS, a combination thereof, and/or the like. The first UE may perform, ina sensing window, sensing to determine whether resources are available,in a selection window, to the second UE, the third UE, one or more otherUEs associated with the BS, a combination thereof, and/or the like.After performing the sensing, the first UE may generate a set ofdevice-to-device coordination messages to transmit to the second UE, thethird UE, the BS, a combination thereof, and/or the like. However, thefirst UE may have a single transmission resource on which a plurality ofdevice-to-device coordination messages are to be transmitted.Additionally, or alternatively, the first UE may have a plurality ofconcurrent resources on which to transmit a plurality ofdevice-to-device coordination messages. However, a quantity ofdevice-to-device coordination messages that the first UE is to transmitmay be greater than concurrent transmission capability of the first UE.

Some aspects described herein provide techniques for message handlingfor device-to-device coordination messages. For example, the first UEmay prioritize the set of device-to-device coordination messagesaccording to a triggering event for a device-to-device coordinationmessage, a source of a request for a device-to-device coordinationmessage, or a type of transmission of a device-to-device coordinationmessage among other factors described in more detail herein. Based atleast in part on prioritizing the set of device-to-device coordinationmessages, the first UE may drop a first one or more device-to-devicecoordination messages and transmit a second one or more device-to-devicecoordination messages. In this way, the first UE can handle excessrequests for device-to-device coordination messages.

FIG. 8 is a diagram illustrating an example 800 associated with messagehandling for device-to-device coordination messages, in accordance withvarious aspects of the present disclosure. As shown in FIG. 8 , example800 includes communication between a group of UEs 120, such as a UE 120a, a UE 120 e, and a UE 120 f. In some aspects, the UEs 120 may beincluded in a wireless network, such as wireless network 100. The UEs120 may communicate on device-to-device links, which may include asidelink.

As further shown in FIG. 8 , and by reference number 810, UE 120 a mayreceive a request for a device-to-device coordination message. Forexample, UE 120 a may receive a first request for a sidelink inter-UEcoordination message from UE 120 e and a second request for a sidelinkinter-UE coordination message from UE 120 f. Additionally, oralternatively, UE 120 a may receive requests for a report regardingresource availability from one or more other devices, such as additionalrequests for sidelink inter-UE coordination messages from additionalUEs, a request for a resource availability report from a BS, acombination thereof, and/or the like.

As further shown in FIG. 8 , and by reference number 820, UE 120 a mayperform resource sensing. For example, as described above, UE 120 a maymonitor resource utilization during a sensing window to predict aresource utilization during a selection window. In some aspects, UE 120a may detect a resource reservation during monitoring of the sensingwindow. For example, UE 120 a may detect, during monitoring of thesensing window, an SCI from UE 120 e indicating an attempt to reserveresources in the selection window. Additionally, or alternatively, UE120 a may detect an SCI from UE 120 f, SCIs from both UE 120 e and 120f, an SCI from another UE, a combination thereof, and/or the like.

As further shown in FIG. 8 , and by reference number 830, UE 120 a maydrop one or more reports. For example, UE 120 a may drop one or moreinter-UE coordination messages that were scheduled for transmission. Insome aspects, UE 120 a may drop the one or more inter-UE coordinationmessages based at least in part on determining that a quantity (e.g., atotal quantity) of inter-UE coordination messages satisfies a threshold.For example, UE 120 a may determine that more than one inter-UEcoordination message is scheduled for transmission using a singleresource and may determine to drop one or more inter-UE coordinationmessages that are scheduled for transmission using the single resource.Additionally, or alternatively, UE 120 a may determine that UE 120 a hasa capability of transmitting a particular quantity of concurrentinter-UE coordination messages and may determine that an actual quantityof inter-UE coordination messages scheduled for concurrent transmissionexceeds the particular quantity.

In some aspects, UE 120 a may drop one or more inter-UE coordinationmessages based at least in part on a prioritization rule. For example,UE 120 a may receive information (e.g., from a BS) identifying aprioritization rule for UE 120 a, for a resource pool that includes UE120 a, for a carrier on which UE 120 a is operating, for a bandwidthpart on which UE 120 a is operating, a combination thereof, and/or thelike, and may implement the prioritization rule to select which inter-UEcoordination messages to transmit or drop.

In some aspects, UE 120 a may prioritize inter-UE coordination messagesbased at least in part on a requesting device type. For example, UE 120a may determine to prioritize report requests from a BS (e.g., directlyfrom the BS or relayed by another UE from the BS) above report requestsfrom UEs 120 e and 120 f. Additionally, or alternatively, UE 120 a mayprioritize report requests from a particular UE that is serving as asidelink transmission UE for UE 120 a. For example, when UE 120 acommunicates with a BS via a relay connection provided by UE 120 e, UE120 a may prioritize a request for an inter-UE coordination message fromUE 120 e over requests from other UEs, such as UE 120 f.

In some aspects, UE 120 a may prioritize inter-UE coordination messagesfor transmission or dropping based at least in part on another factor.For example, UE 120 a may prioritize inter-UE coordination messagesbased at least in part on respective priority levels of requests for theinter-UE coordination messages. Additionally, or alternatively, UE 120 amay prioritize inter-UE coordination messages based at least in part ona source identifier of a requesting UE, a zone identifier of arequesting UE, a zone identifier of a receive UE associated with therequesting UE (e.g., a UE for which the requesting UE is a transmittingUE providing sidelink relay), a combination thereof, and/or the like.Further to the aforementioned example, when UE 120 a is closer (e.g.,based at least in part on zone identifier) to UE 120 e than to UE 120 f,UE 120 a may prioritize transmitting an inter-UE coordination message toUE 120 e over transmitting an inter-UE coordination message to UE 120 f.

Additionally, or alternatively, UE 120 a may prioritize inter-UEcoordination messages based at least in part on respective transmissiontypes. For example, UE 120 a may prioritize a broadcast or groupcastinter-UE coordination message directed to a plurality of UEs over aunicast inter-UE coordination message directed to a single UE.Additionally, or alternatively, UE 120 a may prioritize transmittinginter-UE coordination messages triggered by requests with lower RSRPvalues than other requests. In other words, when UE 120 e transmits arequest with a first RSRP value and UE 120 f transmits a request with asecond RSRP value that is higher than the first RSRP value, UE 120 a mayprioritize transmitting the inter-UE coordination message to UE 120 e.

Additionally, or alternatively, UE 120 a may prioritize inter-UEcoordination messages based at least in part on an ordering of requests.For example, when UE 120 e requests the inter-UE coordination messagebefore UE 120 f, UE 120 a may prioritize transmitting the inter-UEcoordination message to UE 120 e over UE 120 f. In some aspects, UE 120a may use a tiebreaking rule for prioritizing inter-UE coordinationmessages. For example, UE 120 a may select, for dropping or fortransmission, equally prioritized inter-UE coordination messages basedat least in part on a random selection rule, a sequential rule, acombination thereof, and/or the like.

Although some aspects are described herein in terms of a particularprioritization rule or factor, UE 120 a may use a combination of one ormore factors, which may be defined for UE 120 a in a specification ordefined on an implementation basis for UE 120 a.

As further shown in FIG. 8 , and by reference number 840, UE 120 a maytransmit one or more device-to-device coordination messages (that werenot dropped in connection with prioritizing a set of device-to-devicecoordination messages). For example, UE 120 a may transmit a firstinter-UE coordination message identifying a resource availability in theselection window to UE 120 e (and may forgo transmitting a secondinter-UE coordination message to UE 120 f, having dropped the secondinter-UE coordination message in accordance with a prioritization rule).In some aspects, UE 120 e may interpret the inter-UE coordinationmessage to determine whether a resource is available or unavailable,thereby enabling UE 120 e to transmit in the selection window.

As indicated above, FIG. 8 is provided as an example. Other examples maydiffer from what is described with respect to FIG. 8 .

FIG. 9 is a diagram illustrating an example process 900 performed, forexample, by a UE, in accordance with various aspects of the presentdisclosure. Example process 900 is an example where the UE (e.g., UE120) performs operations associated with message handling fordevice-to-device coordination messages.

As shown in FIG. 9 , in some aspects, process 900 may includedetermining that a quantity of device-to-device coordination messagesfor transmission exceeds a threshold (block 910). For example, the UE(e.g., using determination component 1010 depicted in FIG. 10 ) maydetermine that a quantity (e.g., a total quantity) of device-to-devicecoordination messages for transmission exceeds a threshold, as describedabove.

As shown in FIG. 9 , in some aspects, process 900 may includedetermining a prioritization of the device-to-device coordinationmessages for transmission (block 920). For example, the UE (e.g., usingdetermination component 1010) may determine a prioritization of thedevice-to-device coordination messages for transmission, as describedabove.

As further shown in FIG. 9 , in some aspects, process 900 may includedropping a first one or more device-to-device coordination messages(block 930). For example, the UE (e.g., using dropping component 1012depicted in FIG. 10 ) may drop a first one or more device-to-devicecoordination messages according to a message dropping criterion based atleast in part on determining that the quantity of device-to-devicecoordination messages exceeds the threshold, as described above.

As shown in FIG. 9 , in some aspects, process 900 may includetransmitting a second one or more device-to-device coordination messages(block 940). For example, the UE (e.g., using transmission component1006 depicted in FIG. 10 ) may transmit a second one or moredevice-to-device coordination messages based at least in part ondropping the one or more device-to-device coordination messages, asdescribed above.

Process 900 may include additional aspects, such as any single aspect orany combination of aspects described below and/or in connection with oneor more other processes described elsewhere herein.

In a first aspect, process 900 includes transmitting, using transmissioncomponent 1006, the second one or more device-to-device coordinationmessages based at least in part on dropping the first one or moredevice-to-device coordination messages, wherein the second one or moredevice-to-device coordination messages does not exceed the threshold.

In a second aspect, alone or in combination with the first aspect,dropping the first one or more device-to-device coordination messagescomprises determining a prioritization of the set of device-to-devicecoordination messages, and dropping the first one or moredevice-to-device coordination messages based at least in part on theprioritization of the device-to-device coordination messages.

In a third aspect, alone or in combination with one or more of the firstand second aspects, the prioritization, for a device-to-devicecoordination message of the set of device-to-device coordinationmessages, is based at least in part on a characteristic of a device thattriggers the device-to-device coordination message.

In a fourth aspect, alone or in combination with one or more of thefirst through third aspects, the prioritization, for a device-to-devicecoordination message of the set of device-to-device coordinationmessages, is based at least in part on at least one of a priority levelof the device-to-device coordination message, a source identifier of aUE that requested the device-to-device coordination message, a zoneidentifier of the UE that requested the device-to-device coordinationmessage, a zone identifier of another UE associated with the UE thatrequested the device-to-device coordination message, a type of data thatis to be transmitted based at least in part on a result of thedevice-to-device coordination message, a reference signal received powerof a request for the device-to-device coordination message, a timing ofthe device-to-device coordination message, or a combination thereof.

In a fifth aspect, alone or in combination with one or more of the firstthrough fourth aspects, process 900 includes receiving, using receptioncomponent 1002, signaling identifying a configuration of the messagedropping criterion, wherein the configuration is on at least one of aper UE basis, a per resource pool basis, a per carrier basis, a perbandwidth part basis, or a combination thereof.

In a sixth aspect, alone or in combination with one or more of the firstthrough fifth aspects, the message dropping criterion is a UEconfiguration.

In a seventh aspect, alone or in combination with one or more of thefirst through sixth aspects, the message dropping criterion includes arandom message dropping procedure.

Although FIG. 9 shows example blocks of process 900, in some aspects,process 900 may include additional blocks, fewer blocks, differentblocks, or differently arranged blocks than those depicted in FIG. 9 .Additionally, or alternatively, two or more of the blocks of process 900may be performed in parallel.

FIG. 10 is a block diagram of an example apparatus 1000 for wirelesscommunication in accordance with various aspects of the presentdisclosure. The apparatus 1000 may be a UE, or a UE may include theapparatus 1000. In some aspects, the apparatus 1000 includes a receptioncomponent 1002, a communication manager 1004, and a transmissioncomponent 1006, which may be in communication with one another (forexample, via one or more buses). As shown, the apparatus 1000 maycommunicate with another apparatus 1008 (such as a UE, a base station,or another wireless communication device) using the reception component1002 and the transmission component 1006.

In some aspects, the apparatus 1000 may be configured to perform one ormore operations described herein in connection with FIG. 8 .Additionally, or alternatively, the apparatus 1000 may be configured toperform one or more processes described herein, such as process 900 ofFIG. 9 or a combination thereof. In some aspects, the apparatus 1000 mayinclude one or more components of the UE described above in connectionwith FIG. 2 .

The reception component 1002 may receive communications, such asreference signals, control information, data communications, or acombination thereof, from the apparatus 1008. The reception component1002 may receive signaling identifying a configuration of the messagedropping criterion. The reception component 1002 may provide receivedcommunications to one or more other components of the apparatus 1000,such as the communication manager 1004. In some aspects, the receptioncomponent 1002 may perform signal processing on the receivedcommunications (such as filtering, amplification, demodulation,analog-to-digital conversion, demultiplexing, deinterleaving,de-mapping, equalization, interference cancellation, or decoding, amongother examples), and may provide the processed signals to the one ormore other components. In some aspects, the reception component 1002 mayinclude one or more antennas, a demodulator, a MIMO detector, a receiveprocessor, a controller/processor, a memory, or a combination thereof,of the UE described above in connection with FIG. 2 .

The transmission component 1006 may transmit communications, such asreference signals, control information, data communications, or acombination thereof, to the apparatus 1008. The transmission component1006 may transmit a set of device-to-device coordination messages basedat least in part on dropping the one or more device-to-devicecoordination messages. In some aspects, the communication manager 1004may generate communications and may transmit the generatedcommunications to the transmission component 1006 for transmission tothe apparatus 1008. In some aspects, the transmission component 1006 mayperform signal processing on the generated communications (such asfiltering, amplification, modulation, digital-to-analog conversion,multiplexing, interleaving, mapping, or encoding, among other examples),and may transmit the processed signals to the apparatus 1008. In someaspects, the transmission component 1006 may include one or moreantennas, a modulator, a transmit MIMO processor, a transmit processor,a controller/processor, a memory, or a combination thereof, of the UEdescribed above in connection with FIG. 2 . In some aspects, thetransmission component 1006 may be co-located with the receptioncomponent 1002 in a transceiver.

The communication manager 1004 may determine that a quantity ofdevice-to-device coordination messages for transmission exceeds athreshold. The communication manager 1004 may drop one or moredevice-to-device coordination messages according to a message droppingcriterion based at least in part on determining that the quantity ofdevice-to-device coordination messages exceeds the threshold. In someaspects, the communication manager 1004 may include acontroller/processor, a memory, a scheduler, a communication unit, or acombination thereof, of the UE described above in connection with FIG. 2.

In some aspects, the communication manager 1004 may include a set ofcomponents, such as a determination component 1010, a dropping component1012, or a combination thereof. Alternatively, the set of components maybe separate and distinct from the communication manager 1004. In someaspects, one or more components of the set of components may include ormay be implemented within a controller/processor, a memory, a scheduler,a communication unit, or a combination thereof, of the UE describedabove in connection with FIG. 2 . Additionally, or alternatively, one ormore components of the set of components may be implemented at least inpart as software stored in a memory. For example, a component (or aportion of a component) may be implemented as instructions or codestored in a non-transitory computer-readable medium and executable by acontroller or a processor to perform the functions or operations of thecomponent.

The determination component 1010 may determine that a quantity ofdevice-to-device coordination messages for transmission exceeds athreshold, determine a prioritization of the device-to-devicecoordination messages for transmission, a combination thereof, and/orthe like. The dropping component 1012 may drop one or moredevice-to-device coordination messages according to a message droppingcriterion based at least in part on the determination component 1010determining that the quantity of device-to-device coordination messagesexceeds the threshold. The transmission component 1006 may transmit oneor more device-to-device coordination messages, such that a quantity ofthe transmitted one or more device-to-device coordination messages doesnot exceed the threshold.

The number and arrangement of components shown in FIG. 10 are providedas an example. In practice, there may be additional components, fewercomponents, different components, or differently arranged componentsthan those shown in FIG. 10 . Furthermore, two or more components shownin FIG. 10 may be implemented within a single component, or a singlecomponent shown in FIG. 10 may be implemented as multiple, distributedcomponents. Additionally, or alternatively, a set of (one or more)components shown in FIG. 10 may perform one or more functions describedas being performed by another set of components shown in FIG. 10 .

FIG. 11 is a diagram illustrating an example 1100 of a hardwareimplementation for an apparatus 1105 employing a processing system 1110.The apparatus 1105 may be a UE.

The processing system 1110 may be implemented with a bus architecture,represented generally by the bus 1115. The bus 1115 may include anynumber of interconnecting buses and bridges depending on the specificapplication of the processing system 1110 and the overall designconstraints. The bus 1115 links together various circuits including oneor more processors and/or hardware components, represented by theprocessor 1120, the illustrated components, and the computer-readablemedium/memory 1125. The bus 1115 may also link various other circuits,such as timing sources, peripherals, voltage regulators, powermanagement circuits, and/or the like.

The processing system 1110 may be coupled to a transceiver 1130. Thetransceiver 1130 is coupled to one or more antennas 1135. Thetransceiver 1130 provides a means for communicating with various otherapparatuses over a transmission medium. The transceiver 1130 receives asignal from the one or more antennas 1135, extracts information from thereceived signal, and provides the extracted information to theprocessing system 1110, specifically the reception component 1002. Inaddition, the transceiver 1130 receives information from the processingsystem 1110, specifically the transmission component 1006, and generatesa signal to be applied to the one or more antennas 1135 based at leastin part on the received information.

The processing system 1110 includes a processor 1120 coupled to acomputer-readable medium/memory 1125. The processor 1120 is responsiblefor general processing, including the execution of software stored onthe computer-readable medium/memory 1125. The software, when executed bythe processor 1120, causes the processing system 1110 to perform thevarious functions described herein for any particular apparatus. Thecomputer-readable medium/memory 1125 may also be used for storing datathat is manipulated by the processor 1120 when executing software. Theprocessing system further includes at least one of the illustratedcomponents. The components may be software modules running in theprocessor 1120, resident/stored in the computer-readable medium/memory1125, one or more hardware modules coupled to the processor 1120, orsome combination thereof.

In some aspects, the processing system 1110 may be a component of the UE120 and may include the memory 282 and/or at least one of the TX MIMOprocessor 266, the RX processor 258, and/or the controller/processor280. In some aspects, the apparatus 1105 for wireless communicationincludes means for determining that a quantity of device-to-devicecoordination messages for transmission exceeds a threshold, means fordropping one or more device-to-device coordination messages according toa message dropping criterion based at least in part on determining thatthe quantity of device-to-device coordination messages exceeds thethreshold, a combination thereof, and/or the like. The aforementionedmeans may be one or more of the aforementioned components of theapparatus 1000 and/or the processing system 1110 of the apparatus 1105configured to perform the functions recited by the aforementioned means.As described elsewhere herein, the processing system 1110 may includethe TX MIMO processor 266, the RX processor 258, and/or thecontroller/processor 280. In one configuration, the aforementioned meansmay be the TX MIMO processor 266, the RX processor 258, and/or thecontroller/processor 280 configured to perform the functions and/oroperations recited herein.

FIG. 11 is provided as an example. Other examples may differ from whatis described in connection with FIG. 11 .

FIG. 12 is a diagram illustrating an example 1200 of an implementationof code and circuitry for an apparatus 1205. The apparatus 1205 may be aUE.

As further shown in FIG. 12 , the apparatus may include circuitry fordetermining that a quantity of messages exceeds a threshold (circuitry1220). For example, the apparatus may include circuitry to enable theapparatus to determine that a quantity of device-to-device coordinationmessages for transmission exceeds a threshold.

As further shown in FIG. 12 , the apparatus may include circuitry fordropping one or more messages (circuitry 1225). For example, theapparatus may include circuitry to enable the apparatus to drop one ormore device-to-device coordination messages according to a messagedropping criterion based at least in part on determining that thequantity of device-to-device coordination messages exceeds thethreshold.

As further shown in FIG. 12 , the apparatus may include circuitry fortransmitting a set of messages (circuitry 1230). For example, theapparatus may include circuitry to transmit a set of device-to-devicecoordination messages based at least in part on dropping the one or moredevice-to-device coordination messages.

As further shown in FIG. 12 , the apparatus may include circuitry fordetermining a prioritization (circuitry 1235). For example, theapparatus may include circuitry to enable the apparatus to determine aprioritization of the device-to-device coordination messages fortransmission.

As further shown in FIG. 12 , the apparatus may include circuitry forreceiving signaling identifying a message dropping criterion (circuitry1240). For example, the apparatus may include circuitry to enable theapparatus to receive signaling identifying a configuration of themessage dropping criterion, wherein the configuration is on at least oneof a per UE basis, a per resource pool basis, a per carrier basis, a perbandwidth part basis, a combination thereof, and/or the like.

As further shown in FIG. 12 , the apparatus may include, stored incomputer-readable medium 1125, code for determining that a quantity ofmessages exceeds a threshold (code 1250). For example, the apparatus mayinclude code that, when executed by the processor 1120, may cause theprocessor 1120 determine that a quantity of device-to-devicecoordination messages for transmission exceeds a threshold.

As further shown in FIG. 12 , the apparatus may include, stored incomputer-readable medium 1125, code for dropping one or more messages(code 1255). For example, the apparatus may include code that, whenexecuted by the processor 1120, may cause the transceiver 1130 to dropone or more device-to-device coordination messages according to amessage dropping criterion based at least in part on determining thatthe quantity of device-to-device coordination messages exceeds thethreshold.

As further shown in FIG. 12 , the apparatus may include, stored incomputer-readable medium 1125, code for transmitting a set of messages(code 1260). For example, the apparatus may include code that, whenexecuted by the processor 1120, may cause the transceiver 1130 totransmit a set of device-to-device coordination messages based at leastin part on dropping the one or more device-to-device coordinationmessages.

As further shown in FIG. 12 , the apparatus may include, stored incomputer-readable medium 1125, code for determining a prioritization(code 1265). For example, the apparatus may include code that, whenexecuted by the processor 1120, may cause the processor 1120 todetermine a prioritization of the device-to-device coordination messagesfor transmission.

As further shown in FIG. 12 , the apparatus may include, stored incomputer-readable medium 1125, code for receiving signaling identifyinga message dropping criterion (code 1270). For example, the apparatus mayinclude code that, when executed by the processor 1120, may cause thetransceiver 1130 to receive signaling identifying a configuration of themessage dropping criterion.

FIG. 12 is provided as an example. Other examples may differ from whatis described in connection with FIG. 12 .

The following provides an overview of some Aspects of the presentdisclosure:

Aspect 1: A method of wireless communication performed by a userequipment (UE), comprising: dropping a first one or moredevice-to-device coordination messages for transmission, of a set ofdevice-to-device coordination messages, according to a message droppingcriterion in connection with a quantity of device-to-device coordinationmessages in the set of device-to-device coordination messages exceedinga threshold; and transmitting a second one or more device-to-devicecoordination messages of the set of device-to-device coordinationmessages, such that a quantity of transmitted device-to-devicecoordination messages, of the set of device-to-device coordinationmessages, does not exceed the threshold.

Aspect 2: The method of Aspect 1, further comprising: determining that aquantity of device-to-device coordination messages for transmissionexceeds a threshold; and dropping the first one or more device-to-devicecoordination messages based on determining that the quantity ofdevice-to-device coordination messages exceeds the threshold.

Aspect 3: The method of any of Aspects 1 to 2, wherein dropping the oneor more device-to-device coordination messages comprises: determining aprioritization of the set of device-to-device coordination messages; anddropping the first one or more device-to-device coordination messagesbased at least in part on the prioritization of the set ofdevice-to-device coordination messages.

Aspect 4: The method of Aspect 3, wherein the prioritization, for adevice-to-device coordination message of the set of device-to-devicecoordination messages, is based at least in part on a characteristic ofa device that triggers the device-to-device coordination message.

Aspect 5: The method of any of Aspects 3 to 4, wherein theprioritization, for a device-to-device coordination message of the setof device-to-device coordination messages, is based at least in part onat least one of: a priority level of the device-to-device coordinationmessage, a source identifier of a UE that requested the device-to-devicecoordination message, a zone identifier of the UE that requested thedevice-to-device coordination message, a zone identifier of another UEassociated with the UE that requested the device-to-device coordinationmessage, a type of data that is to be transmitted based at least in parton a result of the device-to-device coordination message, a referencesignal received power of a request for the device-to-device coordinationmessage, a timing of the device-to-device coordination message, or acombination thereof.

Aspect 6: The method of any of Aspects 1 to 5, further comprising:receiving signaling identifying a configuration of the message droppingcriterion, wherein the configuration is on at least one of a per UEbasis, a per resource pool basis, a per carrier basis, a per bandwidthpart basis, or a combination thereof.

Aspect 7: The method of any of Aspects 1 to 6, wherein the messagedropping criterion is a UE configuration.

Aspect 8: The method of any of Aspects 1 to 7, wherein the messagedropping criterion includes a random message dropping procedure.

Aspect 9: An apparatus for wireless communication at a device,comprising a processor; memory coupled with the processor; andinstructions stored in the memory and executable by the processor tocause the apparatus to perform the method of one or more of Aspects 1-8.

Aspect 10: A device for wireless communication, comprising a memory andone or more processors coupled to the memory, the one or more processorsconfigured to perform the method of one or more of Aspects 1-8.

Aspect 11: An apparatus for wireless communication, comprising at leastone means for performing the method of one or more of Aspects 1-8.

Aspect 12: A non-transitory computer-readable medium storing code forwireless communication, the code comprising instructions executable by aprocessor to perform the method of one or more of Aspects 1-8.

Aspect 13: A non-transitory computer-readable medium storing a set ofinstructions for wireless communication, the set of instructionscomprising one or more instructions that, when executed by one or moreprocessors of a device, cause the device to perform the method of one ormore of Aspects 1-8.

The foregoing disclosure provides illustration and description but isnot intended to be exhaustive or to limit the aspects to the preciseforms disclosed. Modifications and variations may be made in light ofthe above disclosure or may be acquired from practice of the aspects.

As used herein, the term “component” is intended to be broadly construedas hardware and/or a combination of hardware and software. “Software”shall be construed broadly to mean instructions, instruction sets, code,code segments, program code, programs, subprograms, software modules,applications, software applications, software packages, routines,subroutines, objects, executables, threads of execution, procedures,and/or functions, among other examples, whether referred to as software,firmware, middleware, microcode, hardware description language, orotherwise. As used herein, a “processor” is implemented in hardwareand/or a combination of hardware and software. It will be apparent thatsystems and/or methods described herein may be implemented in differentforms of hardware and/or a combination of hardware and software. Theactual specialized control hardware or software code used to implementthese systems and/or methods is not limiting of the aspects. Thus, theoperation and behavior of the systems and/or methods are describedherein without reference to specific software code, since those skilledin the art will understand that software and hardware can be designed toimplement the systems and/or methods based, at least in part, on thedescription herein.

As used herein, “satisfying a threshold” may, depending on the context,refer to a value being greater than the threshold, greater than or equalto the threshold, less than the threshold, less than or equal to thethreshold, equal to the threshold, not equal to the threshold, or thelike.

Even though particular combinations of features are recited in theclaims and/or disclosed in the specification, these combinations are notintended to limit the disclosure of various aspects. Many of thesefeatures may be combined in ways not specifically recited in the claimsand/or disclosed in the specification. The disclosure of various aspectsincludes each dependent claim in combination with every other claim inthe claim set. As used herein, a phrase referring to “at least one of” alist of items refers to any combination of those items, including singlemembers. As an example, “at least one of: a, b, or c” is intended tocover a, b, c, a+b, a+c, b+c, and a+b+c, as well as any combination withmultiples of the same element (e.g., a+a, a+a+a, a+a+b, a+a+c, a+b+b,a+c+c, b+b, b+b+b, b+b+c, c+c, and c+c+c, or any other ordering of a, b,and c).

No element, act, or instruction used herein should be construed ascritical or essential unless explicitly described as such. Also, as usedherein, the articles “a” and “an” are intended to include one or moreitems and may be used interchangeably with “one or more.” Further, asused herein, the article “the” is intended to include one or more itemsreferenced in connection with the article “the” and may be usedinterchangeably with “the one or more.” Furthermore, as used herein, theterms “set” and “group” are intended to include one or more items andmay be used interchangeably with “one or more.” Where only one item isintended, the phrase “only one” or similar language is used. Also, asused herein, the terms “has,” “have,” “having,” or the like are intendedto be open-ended terms that do not limit an element that they modify(e.g., an element “having” A may also have B). Further, the phrase“based on” is intended to mean “based, at least in part, on” unlessexplicitly stated otherwise. Also, as used herein, the term “or” isintended to be inclusive when used in a series and may be usedinterchangeably with “and/or,” unless explicitly stated otherwise (e.g.,if used in combination with “either” or “only one of”).

What is claimed is:
 1. A user equipment (UE) for wireless communication, comprising: a memory; and one or more processors, coupled to the memory, configured to: drop a first one or more device-to-device coordination messages, of a set of device-to-device coordination messages for transmission, according to a message dropping criterion in connection with a quantity of device-to-device coordination messages in the set of device-to-device coordination messages exceeding a threshold; and transmit a second one or more device-to-device coordination messages of the set of device-to-device coordination messages, such that a quantity of transmitted device-to-device coordination messages, of the set of device-to-device coordination messages, does not exceed the threshold.
 2. The UE of claim 1, wherein the threshold is based at least in part on a capability of a target for at least one of the second one or more device-to-device coordination messages.
 3. The UE of claim 1, wherein the one or more processors, to drop the first one or more device-to-device coordination messages, are configured to: determine a prioritization of the set of device-to-device coordination messages; and drop the first one or more device-to-device coordination messages based at least in part on the prioritization of the set of device-to-device coordination messages.
 4. The UE of claim 3, wherein the prioritization, for a device-to-device coordination message of the set of device-to-device coordination messages, is based at least in part on a characteristic of a device that triggers the device-to-device coordination message.
 5. The UE of claim 3, wherein the prioritization, for a device-to-device coordination message of the set of device-to-device coordination messages, is based at least in part on at least one of: a priority level of the device-to-device coordination message, a source identifier of a UE that requested the device-to-device coordination message, a zone identifier of the UE that requested the device-to-device coordination message, a zone identifier of another UE associated with the UE that requested the device-to-device coordination message, a type of data that is to be transmitted based at least in part on a result of the device-to-device coordination message, a reference signal received power of a request for the device-to-device coordination message, or a timing of the device-to-device coordination message.
 6. The UE of claim 1, wherein the one or more processors are further configured to: receive signaling identifying a configuration of the message dropping criterion, wherein the configuration is on at least one of a per UE basis, a per resource pool basis, a per carrier basis, or a per bandwidth part basis.
 7. The UE of claim 1, wherein the message dropping criterion is a UE configuration.
 8. The UE of claim 1, wherein the message dropping criterion includes a random message dropping procedure.
 9. A non-transitory computer-readable medium storing a set of instructions for wireless communication, the set of instructions comprising: one or more instructions that, when executed by one or more processors of a user equipment (UE), cause the UE to: drop a first one or more device-to-device coordination messages, of a set of device-to-device coordination messages for transmission, according to a message dropping criterion in connection with a quantity of device-to-device coordination messages in the set of device-to-device coordination messages exceeding a threshold; and transmit a second one or more device-to-device coordination messages of the set of device-to-device coordination messages, such that a quantity of transmitted device-to-device coordination messages, of the set of device-to-device coordination messages, does not exceed the threshold.
 10. The non-transitory computer-readable medium of claim 9, wherein the threshold is based at least in part on a capability of a target for at least one of the second one or more device-to-device coordination messages.
 11. The non-transitory computer-readable medium of claim 9, wherein the one or more instructions further cause the UE to: determine a prioritization of the set of device-to-device coordination messages; and drop the first one or more device-to-device coordination messages based at least in part on the prioritization of the set of device-to-device coordination messages.
 12. The non-transitory computer-readable medium of claim 11, wherein the prioritization, for a device-to-device coordination message of the set of device-to-device coordination messages, is based at least in part on a characteristic of a device that triggers the device-to-device coordination message.
 13. The non-transitory computer-readable medium of claim 11, wherein the prioritization, for a device-to-device coordination message of the set of device-to-device coordination messages, is based at least in part on at least one of: a priority level of the device-to-device coordination message, a source identifier of a UE that requested the device-to-device coordination message, a zone identifier of the UE that requested the device-to-device coordination message, a zone identifier of another UE associated with the UE that requested the device-to-device coordination message, a type of data that is to be transmitted based at least in part on a result of the device-to-device coordination message, a reference signal received power of a request for the device-to-device coordination message, or a timing of the device-to-device coordination message.
 14. The non-transitory computer-readable medium of claim 9, wherein the one or more instructions further cause the UE to: receive signaling identifying a configuration of the message dropping criterion, wherein the configuration is on at least one of a per UE basis, a per resource pool basis, a per carrier basis, or a per bandwidth part basis.
 15. The non-transitory computer-readable medium of claim 9, wherein the message dropping criterion is a UE configuration.
 16. The non-transitory computer-readable medium of claim 9, wherein the message dropping criterion includes a random message dropping procedure.
 17. An apparatus for wireless communication, comprising: means for dropping a first one or more device-to-device coordination messages, of a set of device-to-device coordination messages for transmission, according to a message dropping criterion in connection with a quantity of device-to-device coordination messages in the set of device-to-device coordination messages exceeding a threshold; and means for transmitting a second one or more device-to-device coordination messages of the set of device-to-device coordination messages, such that a quantity of transmitted device-to-device coordination messages, of the set of device-to-device coordination messages, does not exceed the threshold.
 18. The apparatus of claim 17, wherein the threshold is based at least in part on a capability of a target for at least one of the second one or more device-to-device coordination messages.
 19. The apparatus of claim 17, further comprising: means for determining a prioritization of the set of device-to-device coordination messages; and means for dropping the first one or more device-to-device coordination messages based at least in part on the prioritization of the set of device-to-device coordination messages.
 20. The apparatus of claim 19, wherein the prioritization, for a device-to-device coordination message of the set of device-to-device coordination messages, is based at least in part on a characteristic of a device that triggers the device-to-device coordination message.
 21. The apparatus of claim 19, wherein the prioritization, for a device-to-device coordination message of the set of device-to-device coordination messages, is based at least in part on at least one of: a priority level of the device-to-device coordination message, a source identifier of a UE that requested the device-to-device coordination message, a zone identifier of the UE that requested the device-to-device coordination message, a zone identifier of another UE associated with the UE that requested the device-to-device coordination message, a type of data that is to be transmitted based at least in part on a result of the device-to-device coordination message, a reference signal received power of a request for the device-to-device coordination message, or a timing of the device-to-device coordination message.
 22. The apparatus of claim 17, further comprising: means for receiving signaling identifying a configuration of the message dropping criterion, wherein the configuration is on at least one of a per UE basis, a per resource pool basis, a per carrier basis, or a per bandwidth part basis.
 23. The apparatus of claim 17, wherein the message dropping criterion is a UE configuration.
 24. The apparatus of claim 17, wherein the message dropping criterion includes a random message dropping procedure.
 25. A method of wireless communication performed by a user equipment (UE), comprising: dropping a first one or more device-to-device coordination messages, of a set of device-to-device coordination messages for transmission, according to a message dropping criterion in connection with a quantity of device-to-device coordination messages in the set of device-to-device coordination messages exceeding a threshold; and transmitting a second one or more device-to-device coordination messages of the set of device-to-device coordination messages, such that a quantity of transmitted device-to-device coordination messages, of the set of device-to-device coordination messages, does not exceed the threshold.
 26. The method of claim 25, wherein the threshold is based at least in part on a capability of a target for at least one of the second one or more device-to-device coordination messages.
 27. The method of claim 25, wherein dropping the first one or more device-to-device coordination messages comprises: determining a prioritization of the set of device-to-device coordination messages; and dropping the first one or more device-to-device coordination messages based at least in part on the prioritization of the set of device-to-device coordination messages.
 28. The method of claim 27, wherein the prioritization, for a device-to-device coordination message of the set of device-to-device coordination messages, is based at least in part on a characteristic of a device that triggers the device-to-device coordination message.
 29. The method of claim 27, wherein the prioritization, for a device-to-device coordination message of the set of device-to-device coordination messages, is based at least in part on at least one of: a priority level of the device-to-device coordination message, a source identifier of a UE that requested the device-to-device coordination message, a zone identifier of the UE that requested the device-to-device coordination message, a zone identifier of another UE associated with the UE that requested the device-to-device coordination message, a type of data that is to be transmitted based at least in part on a result of the device-to-device coordination message, a reference signal received power of a request for the device-to-device coordination message, or a timing of the device-to-device coordination message.
 30. The method of claim 25, further comprising: receiving signaling identifying a configuration of the message dropping criterion, wherein the configuration is on at least one of a per UE basis, a per resource pool basis, a per carrier basis, or a per bandwidth part basis. 